List of Nutrition terms

The study of poultry nutrition involves many terms not commonly used in daily communication. The following is a list of nutritional terms.


A – B

Abscess: A collection of pus in any part of the body.

Absorption: The movement of nutrients or other substances from the digestive tract or through the skin into the blood and/or lymph system.

Acetic acid: One of the volatile fatty acids with the formula CH3COOH. Commonly found in silage, rumen contents, and vinegar.

Additive: An ingredient or a combination of ingredients added, usually in small quantities, to a basic feed mix for the purpose of fortifying the basic mix with certain essential nutrients and/or medicines.

Adipose: Of a fatty nature.

Ad libitum: As desired by the animal. Free access to either feed or water

Adrenal: Near the kidney.

Aerial part: The above-ground part of a plant.

Aerobic: Living or functioning in the presence of air or molecular oxygen.

Alanine: One of the nonessential amino acids.

Alimentary: Having to do with feed or food.

Alimentary tract: Same as digestive tract.

Amino acid: Any one of a class of organic compounds which contain both the amino (NH2) group and the carboxyl (COOH) group.

Ammoniated: Combined or impregnated with ammonia or an ammonium compound.

Amylase: Any one of several enzymes which effect a hydrolysis of starch to maltose. Examples are pancreatic amylase (amylopsin) and salivary amylase (ptyalin).

Anabolism: The conversion of simple substances into more complex substances by living cells (also called ‘constructive metabolism’).

Anaerobic: Living or functioning in the absence of air or molecular oxygen.

Anemic: Lacking in size and/or number of red blood cells.

Animal protein factor: What was once an unidentified growth factor essential for poultry and swine and present in protein feeds of animal origin. It is now known to be the same as vitamin B2.

Antacid: A substance that counteracts acidity.

Antibiotic: A substance produced by one microorganism which has an inhibiting effect on the growth of another.

Antibody: Substance produced in the body that acts against disease.

Antioxidant: A material capable of chemically protecting other substances from oxidation.

Anus: The posterior end and opening of the digestive tract.

Arachidonic acid: A 20-carbon unsaturated fatty acid having four double bonds.

Arginine: One of the essential amino acids.

Artificially dried: Dried by other than natural means. Dehydrated.

Ascorbic acid: Same as vitamin C, the antiscorbutic vitamin.

As fed: As consumed by the animal.

Ash: The incombustible residue remaining after incineration at 600° C for several hours.

Aspartic acid: One of the nonessential amino acids.

Asphyxia: Suffocation or the suspension of animation as the result of suffocation.

Aspirated: Removal of light materials from heavier material by use of air.

Atrophy: A wasting away of a part of the body.

Avidin: A protein in egg albumen which can combine with biotin to render the latter unavailable to the animal.

Bacteria: Very small, unicellular plant organisms.

Balanced: Containing essential nutrients in the proper proportions.

Balanced daily ration: Such a combination of feeds as will provide the essential nutrients in such amounts as will properly nourish a given animal for a 24-hour period.

Balanced ration: Such a combination of feeds as will provide the essential nutrients in the proper proportions.

Basal metabolism: The heat production of an animal during physical, digestive, and emotional rest.

Bile: A greenish-yellow fluid formed in the liver, stored in the gall bladder (except in the horse which has no gall bladder), and secreted via the bile duct into the upper small intestine. It functions in digestion.

Biochemistry: The chemistry of living things.

Biological function: The role played by a chemical compound in living organisms.

Biological value: The efficiency with which a protein furnishes the proper proportions of the essential amino acids. A protein which has a high biological value is said to be of good quality.

Biosynthesis: The formation of chemical substances from other chemical substances in a living organism.

Biotin: One of the B vitamins.

Boiling point: The temperature at which the vapor pressure of a liquid equals the atmospheric pressure.

Bolted: Separated from parent material by means of a bolting cloth.

Bomb calorimeter: An instrument used for determining the gross energy content of a material.

Bran: The pericarp or seed coat of grain removed during processing.

Buffer: Any substance that can counteract changes in free acid or alkali concentration.

Bushel: A certain volume equal to 2150.42 cubic inches (approximately 1.25 cubic feet).

Butyric acid: One of the volatile fatty acids with the formula CH3CH2CH2COOH. Commonly found in rumen contents and poor quality silage.


C – D

Caecum: Same as cecum.

Calcification: Process by which organic tissue becomes hardened by a deposit of calcium salts.

Caloric: Pertaining to heat or energy.

Calorie: The amount of energy as heat required to raise one gram of water 1°C (precisely from 14.5°C to 15.5°C).

Calorimeter: An instrument for measuring heat.

Calorimetry: The science of measuring heat.

Carbohydrate: Organic substances that contain carbon, hydrogen, and oxygen, with the hydrogen and oxygen present in the same proportions as in water.

Carcass: The body of an animal less the viscera and usually the head, skin, and lower leg.

Carcinogen: Any cancer-producing substance.

Carcinogenic: Cancer-producing.

Cardiovascular: Pertaining to the heart and blood vessels.

Caries: Areas of tooth decay.

Carotene: A yellow organic compound that is a precursor of vitamin A.

Carrier: An edible material which is used to facilitate the addition of micronutrients to a ration.

Cartilage: The gristle or connective tissue attached to the ends of bones.

Casein: The protein precipitated from milk by acid and/or rennin.

Catabolism: The conversion of complex substances into more simple compounds by living cells (also called ‘destructive metabolism’).

Catalyst: A substance that speeds up the rate of a chemical reaction but is not itself used up in the reaction.

Cecum: An intestinal pouch located at the junction of the large and small intestine. Also caecum.

Cell: The structural and functional microscopic unit of plant and animal organisms.

Cell platelet: A small, colorless, disk-shaped cell in the blood concerned with blood coagulation.

Cellulose: A polysaccharide having the formula (C6H10O5)n. Found in the fibrous portion of plants. Low in digestibility.

Celsius: Same as Centigrade.

Centigrade: A thermometer scale in which water freezes at 0° and boils at 100°. Same as Celsius.

Chlorophyll: The green coloring matter present in growing plants.

Cholesterol: The most common member of the sterol group.

Choline: One of the B vitamins.

Chopped: Reduced in particle size by cutting.

Chromatography: A technique for separating complex mixtures of chemical substances.

Citrulline: One of the nonessential amino acids.

Clipped: With oat grain, the more fibrous end has been removed.

Coagulated: Curdled, clotted, or congealed.

Coagulation: The change from a fluid state to a thickened jelly, curd, or clot.

Coenzyme : A partner required by some enzymes to produce enzymatic activity.

Collagen: The main supportive protein of connective tissue.

Colostrum milk: The milk secreted during the first few days of lactation.

Combustion: The combination of substances with oxygen accompanied by the liberation of heat.

Commercial feed: Any material produced by a commercial company and distributed for use as a feed or feed component.

Complete ration: A single feed mixture into which has been included all of the dietary essentials, except water, of a given class of livestock.

Concentrate: Opposite of roughage. Any feed low (under about 20%) in crude fibre and high (over about 60%) in TDN on an air-dry basis.  Also, a concentrated source of one or more nutrients used to enhance the nutritional adequacy of a supplement mix.

Congenital: Existing at birth.

Congestion: Excessive accumulation of blood in a part of the body.

Convulsion: A violent involuntary contraction or series of contractions of the voluntary muscles.

Coronary: Of or relating to the heart.

Creatinine: A nitrogenous compound arising from protein metabolism and secreted in the urine.

Crimped: Having been passed between rollers with corrugated surfaces.

Crude fat: That part of a feed which is soluble in ether. Also referred to as ether extract.

Crude fiber: The more fibrous, less digestible portion of a feed. Consists primarily of cellulose and lignin.

Crude protein: Total ammoniacal nitrogen x 6.25, based on the fact that feed protein on the average contains 16.0% nitrogen.

Curd: The semi-solid mass that is formed when milk comes in contact with an acid or the enzyme rennin. It consists mainly of the protein casein.

Cyanocobalamin: Same as vitamin B12.

Cystine: One of the nonessential amino acids. It is sulfur containing and may be used to meet in part the need for methionine.

Cystitis: Inflammation of the bladder.

Deficiency disease: A disease resulting from an inadequate dietary intake of some nutrient.

Defluorinated: Having had the fluorine content reduced to a level which is nontoxic under normal use.

Dehydrated: Having had most of the moisture removed through artificial drying.

Dermatitis: Inflammation of the skin.

Desiccate: To dry completely.

Dextrin: An intermediate polysaccharide product obtained during starch hydrolysis.

Digestible energy: That part of the gross energy of a feed which does not appear in the feces.

Digestion: The processes involved in the conversion of feed into absorbable forms.

Digestive tract: The passage from the mouth to the anus through which feed passes following consumption as it is subjected to various digestive processes. Primarily the stomach and intestines.

Disaccharide: Any one of several so-called compound sugars which yield two mono-saccharide molecules upon hydrolysis. Sucrose, maltose, and lactose are the most common.

Dispensable amino acid: Basically the same as nonessential amino acid.

Dry matter: That part of feed which is not water (sometimes referred to as dry substance or total solids). Is the sum of the crude protein, crude fat, crude fiber, nitrogen-free extract, and ash.

Dry-rendered: Having been heat processed for the removal of fat without the addition of water or steam.

Duodenum: The upper portion of the small intestine which extends from the stomach to the jejunum.

Dystocia: Difficult parturition.


E – F

Edema: Swelling of a part of or of the entire body due to an accumulation of an excess of water.

Element: Any one of the fundamental atoms of which all matter is composed.

Emaciated: An excessively thin condition of the body.

Emulsify: To disperse small drops of one liquid into another liquid.

Endemic: Occurring in low incidence but more or less constantly in a given population.

Endocrine: Pertaining to internal secretions.

Endogenous: Originating from within the organism.

Endometrium: The mucous membrane that lines the uterus.

Energy: The capacity to perform work.

Ensilage: The same as silage.

Ensiled: Having been subjected to anaerobic fermentation to form silage.

Enteritis: Inflammation of the intestines.

Environmental: Pertaining to surrounding influences.

Enzymatic: Related to an enzyme.

Enzyme: One of a class of organic compounds, formed by living cells, capable of producing or accelerating specific organic reactions. An organic catalyst.

Epidemic: When many individuals in a given region are attacked by some disease at the same time.

Epithelial: Refers to those cells that form the outer layer of the skin and other membranes.

Ergosterol: One of the sterols which upon exposure to ultraviolet light is converted to vitamin D2.

Esophagus: The passageway leading from the mouth to the stomach. Sometimes called the gullet.

Essential amino acid: Any one of several amino acids that are needed by animals and cannot be synthesized by them in the amount needed and so must be present in the protein of the feed as such.

Estrogens: Estrus-producing hormones secreted by the ovaries.

Estrus: The recurring periods of sexual receptivity in female mammals. The period of heat.

Etiology: The causes of a disease or disorder.

Excreta: The products of excretion – primarily feces and urine.

Exogenous: Originating from outside of the organism.

Expanded: As applied to feed – having been increased in volume as the result of a sudden reduction in surrounding pressure.

Expeller process: A process for the mechanical extraction of oil from seeds, involving the use of a screw press.

Extrinsic factor: A factor coming from or originating from outside an organism.

Extruded: As applied to feed—having been forced through a die under pressure.

Factor: In nutrition, any chemical substance found in feed.

Fahrenheit: A thermometer scale in which water freezes at 32° and boils at 212°.

Fat: The product formed when a fatty acid reacts with glycerol. The glyceryl ester of a fatty acid. Stearin, palmitin, and olein are examples.

Fat soluble: Soluble in fats and fat solvents but generally not soluble in water.

Fattening: This is the deposition of unused energy in the form of fat within the body tissues.

Fatty acid: Any one of several organic compounds containing carbon, hydrogen, and oxygen which combine with glycerol to form fat.

Fauna: The animal life present. Frequently used to refer to the overall protozoal population present.

Feces: The excreta discharged from the digestive tract through the anus.

Feed: Any material eaten by an animal as a part of its daily ration.

Feed grade: Suitable for animal but not for human consumption.

Fermentation: Chemical changes brought about by enzymes produced by various microorganisms.

Fetus: The unborn young of animals.

Fibrous: High in content of cellulose and/or lignin.

Finish: To fatten a slaughter animal. Also, the degree of fatness of such an animal.

Fistula: An abnormal tube-like passage from some part of the body to another part or to the exterior—sometimes surgically inserted.

Flaked: Rolled or cut into flat pieces.

Flora: The plant life present. In nutrition it generally refers to the bacteria present in the digestive tract.

Fodder: The entire above-ground part of nearly mature corn or sorghum in the fresh or cured form.

Folacin: Same as folic acid. One of the B vitamins.

Folic acid: Same as folacin, which is one of the B vitamins.

Forage: Crops used as pasture, hay, haylage, silage, or green chop for feeding purposes.

Formula feed: A feed consisting of two or more ingredients mixed in specified proportions.

Fortify: Nutritionally, to add one or more nutrients to a feed.

Fractionation: The laboratory separation of natural materials into their component parts.

Free choice: Free to eat two or more feeds at will.

Fresh: Usually denotes the green or wet form of a feed material.

Fructose: A hexose monosaccharide found especially in ripe fruits and honey. Obtained along with glucose from sucrose hydrolysis. Commonly known as fruit sugar.


G – H

Galactose: A hexose monosaccharide obtained along with glucose from lactose hydrolysis.

Gall bladder: A membranous sac lying next to the liver of all farm livestock, except the horse, in which bile is stored.

Gastric: Pertaining to the stomach.

Gastric juice: A clear liquid secreted by the wall of the stomach. It contains hydrochloric acid and the enzymes rennin, pepsin, and gastric lipase.

Gastritis: Inflammation of the stomach.

Gastroenteritis: Inflammation of the stomach and intestines.

Gastrointestinal: Pertaining to the stomach and intestines.

Genetic: Pertaining to heredity.

Genitourinary: Refers to the organs of reproduction and urine excretion.

Germ: Embryo of a seed.

Gestation: The condition of bearing an unborn fetus. Pregnancy.

Gingivitis: Inflammation of the gums.

Gland: An organ that produces and secretes a chemical substance in the body.

Glucose: A hexose monosaccharide obtained upon the hydrolysis of starch and certain other carbohydrates. Also called dextrose.

Glutamic acid: One of the nonessential amino acids.

Glycerol: An alcohol containing three carbons and three hydroxyl groups.

Glycine: One of the nonessential amino acids.

Glycogen: A polysaccharide with the formula (C6H10O5)n which is formed in the liver and depolymerized to glucose to serve as a ready source of energy when needed by the animal. Known also as animal starch.

Goiter: An enlargement of the thyroid gland located in the neck. Sometimes caused by an iodine deficiency.

Gossypol: A substance present in cottonseed and cottonseed meal which is toxic to swine and certain other non-ruminant animals.

Gravid: Pregnant.

Green chop: Forage harvested and fed in the green, chopped form.

Groat: Grain from which the hull has been removed.

Gross energy: The total heat of combustion of a material as determined by the use of a bomb calorimeter.

Ground: Reduced in particle size by impact, shearing, or attrition.

Growth: An increase in muscle, bone, vital organs, and connective tissue as contrasted to fattening or fat deposition.

Hay: The aerial part of finer-stemmed forage crops stored in the dry form for animal feeding.

Heat increment: The heat which is unavoidably produced by an animal incidental with nutrient digestion and utilization. Was originally called ‘work of digestion’.

Heat labile: Unstable to heat.

Hemoglobin: The oxygen-carrying, red-pigmented protein of the red corpuscles.

Hemorrhage: Copious loss of blood through bleeding.

Hepatitis: Inflammation of the liver.

Hexosan: A hexose-based polysaccharide having the general formula (C6H10O5)n. Cellulose, starch, and glycogen are the most common.

Hexose: A 6-carbon monosaccharide having the formula C6H12O6. Glucose, fructose, and galactose are common examples.

Histidine: One of the essential amino acids.

Homogenized: The fat within a fluid having been reduced to globules so small they remain in suspension for an extended period of time.

Hormone: A chemical substance secreted into the body fluids by an endocrine gland that has a specific effect on other tissues.

Hulls: The outer protective covering of seeds.

Husks: Usually refers to the fibrous covering of an ear of corn.

Hydraulic process: A process for the mechanical extraction of oil from seeds, involving the use of a hydraulic press. Sometimes referred to as the old process.

Hydrogenation: The chemical addition of hydrogen to any unsaturated compound.

Hydrolysis: The splitting of a substance into the smaller units by its chemical reaction with water.

Hydroxyproline: One of the nonessential amino acids.

Hyper: A prefix meaning in excess of the normal.

Hyperemia: An excess of blood in any part of the body.

Hypertension: An abnormally high tension—usually associated with high blood pressure.

Hyperthyroidism: Over-activity of the thyroid gland.

Hypertrophied: Having increased in size independent of natural growth.

Hypervitaminosis: An abnormal condition resulting from the intake of an excess of one or more vitamins.

Hypo: A prefix denoting less than the normal amount.

Hypomagnesemia: An abnormally low level of magnesium in the blood.

Hysteritis: Inflammation of the uterus.


I – J

Ileum: The lower portion of the small intestine extending from the jejunum to the cecum.

Impermeable: Not capable of being penetrated.

Inactivate: To render a substance inactive.

Incidence: The frequency of occurrence of a situation or a condition.

Indispensable amino acid: Essential amino acid.

Inert: Relatively inactive.

Ingest: To eat or take in through the mouth.

Inorganic: Denotes chemical compounds that do not contain carbon in chain structure.

Inositol: One of the B vitamins.

Insulin: A hormone secreted by the pancreas into the blood. It regulates sugar metabolism.

Intestinal juice: A clear liquid secreted by glands in the wall of the small intestine. It contains the enzymes intestinal lactase, maltase, and sucrase, and several peptidases.

Intestinal tract: The small and large intestine.

Intestine, large: The tube-like part of the digestive tract lying between the small intestine and the anus. Larger in diameter but shorter in length than the small intestine.

Intestine, small: The long, tortuous, tube-like part of the digestive tract leading from the stomach to the cecum and large intestine. Smaller in diameter but longer than the large intestine.

Intrinsic factor: A chemical substance in normal stomach juice necessary for the absorption of vitamin B,2.

Insulin: A polysaccharide found especially in Jerusalem artichokes which yields fructose upon hydrolysis.

Iodine number: A number which denotes the degree of unsaturation of a fat or fatty acid. It is the amount of iodine in grams which can be taken up by 100 g of the fat or fatty acid.

Irradiation: The act of treating with ultraviolet light.

Isoleucine: One of the essential amino acids.

Jejunum: The middle portion of the small intestine which extends from the duodenum to the ileum.


K – M

Keratin: A sulfur-containing protein which is the primary component of epidermis, hair, wool, hoof, horn and the organic matrix of the teeth.

Kernel: A dehulled seed.

Kilocalorie: 1,000 calories.

Labile: Unstable. Easily destroyed.

Lactase: An enzyme present in intestinal juice which acts on lactose to produce glucose and galactose.

Lactation: The secretion of milk.

Lactic Acid An organic acid, one form (CH3CHOH-COOH) of which is commonly found in sour milk, sauerkraut, and silage. Other forms enter into body metabolism.

Lactose: A disaccharide found in milk having the formula C12H22O11. It hydrolyzes to glucose and galactose. Commonly known as milk sugar.

Ld50: A dose which is lethal for 50% of the test animals.

Lesion: Any unhealthy change in the structure of a part of the body.

Leucine: One of the essential amino acids.

Lignin: An indigestible compound which along with cellulose is a major component of the cell wall of certain plant materials such as wood, hulls, straws, and overripe hays.

Linoleic acid: An 18-carbon unsaturated fatty acid having two double bonds. It reacts with glycerol to form linolein.

Linolein: An unsaturated fat formed from the reaction of linoleic acid with glycerol.

Linolenic acid: An 18-carbon unsaturated fatty acid having three double bonds.

Lipase: A fat-splitting enzyme. Gastric lipase is present in gastric juice and pancreatic lipase is present in pancreatic juice. Both act on fats to produce fatty acids and glycerol.

Lipids: A broad term for fats and fat-like substances.

Lymph: The slightly yellow, transparent fluid occupying the lymphatic
channels of the body.

Lysine: One of the essential amino acids.

Malformation: Any abnormal development of a part of the body.

Malignant: Virulent or destructive as applied to cancer.

Maltase: An enzyme which acts on maltose to produce glucose. Salivary maltase is in saliva, and intestinal maltase is in intestinal juice.

Maltose: A disaccharide having the formula C12H22O11. Obtained from the partial hydrolysis of starch. It hydrolyzes to glucose.

Mammary glands: The milk-secreting glands.

Manure: The refuse from animal quarters consisting of excreta with or without litter or bedding.

Matrix: The intercellular framework of a tissue.

Meal: A feed ingredient having a particle size somewhat larger than flour.

Mechanically extracted: Having had its fat content removed by the application of heat and mechanical pressure. The hydraulic and expeller processes are both methods of mechanical extraction.

Medium: A nutrient substrate used for supporting the growth of microorganisms.

Megacalorie: 1,000 kilocalories or 1,000,000 calories.

Metabolism: The sum of all the physical and chemical processes taking place in a living organism.

Metabolite: Any substance produced by metabolism.

Metabolizable energy: Digestible energy minus the energy of the urine and fermentation gases.

Methionine: One of the essential amino acids. It is sulfur containing and may be replaced in part by cystine.

Metritis: Inflammation of the uterus.

Microbe: Same as microorganism.

Microbiological: Pertaining to microorganisms.

Microflora: The gross overall bacterial population present. Is sometimes used to include the protozoa as well as the bacteria.

Microgram: One millionth of a gram or one thousandth of a milligram.

Micro-ingredient: Any ration component normally measured in milligrams or micrograms per kilogram or in parts per million.

Microorganism: A very small living organism—usually microscopic in size.

Middlings: A by-product of flour milling consisting of varying proportions of small particles of bran, endosperm, and germ.

Milligram: One-thousandth of a gram.

Mill run: A product as it comes from the mill, having no definite specifications

Miscible: Capable of being mixed easily with another substance.

Molasses: A thick, viscous, usually dark colored, liquid product containing a high concentration of soluble carbohydrates, minerals, and certain other materials.

Molecule: A chemical combination of two or more atoms.

Monosaccharide: Any one of several simple, non-hydrolyzable sugars. Glucose, fructose, galactose, arabinose, xylose, and ribose are examples.

Morbidity: A state of sickness.

Moribund: In a dying state—near death.

Mucosa: The membrane that lines the passages and cavities of the body.

Mucous membrane: A membrane lining the cavities and canals of the body, kept moist by mucus.

Mucus: A slimy liquid secreted by the mucous glands and membranes.

Mycotoxin: A fungous or bacterial toxin. Sometimes present in feed material.


N – P

Necrosis: Death of a part of the cells making up a living tissue.

Neonate: A newly born animal.

Nephritis: Inflammation of the kidneys.

Net energy: This is that part of metabolizable energy over the use of which the animal has complete control. It is metabolizable energy minus the heat increment.

Neuritic: Pertaining to the nerves.

New process: Pertains to the extraction of oil from seeds. Same as ex-peller process.

Niacin: Same as nicotinic acid and niacin. Is one of the B vitamins. Nicotinamide also has niacin activity. The amide of nicotinic acid. It has niacin activity. One of the B vitamins.

Nicotinamide nicotinic acid nitrogen-free extract: That part of feed dry matter which is not crude protein, crude fat, crude fiber, or ash. It consists mostly of sugars and starches. Sometimes referred to as NFE.

Non-essential amino acid: Any one of several amino acids that are required by animals but which can be synthesized in adequate amounts by an animal in its tissues from other amino acids.

Non-protein: Any one of a group of ammoniacal nitrogen containing compounds which are not true proteins. Urea is a common example.

Non-ruminant: A simple-stomached animal that does not ruminate. Examples are swine, horses, dogs, and humans.

Nutrient: Any chemical compound having specific functions in the nutritive support of animal life.

Nutriture: Nutritional status.

Obese: Being overweight due to a surplus of body fat.

Oil: Usually a mixture of pure fats which is liquid at room temperature.

Old process: Pertains to the extraction of oil from seeds. Same as hydraulic process.

Oleic acid: An 18-carbon unsaturated fatty acid (one double bond) which reacts with glycerol to form olein.

Olein: The fat formed from the reaction of oleic acid with glycerol.

Omasum: The third compartment of a ruminant’s stomach. Sometimes called the manyplies.

Organic: Refers to chemical compounds that contain carbon in chain structure.

Organic Acid: Any organic compound that contains a carboxyl group (COOH).

Orts: That portion of an animal’s feed which it refuses to eat.

Osmosis: The passage of a solute or a solution through a semi-permeable membrane toward effecting an equalization of the concentration of the fluids on opposite sides of the membrane.

Osmotic Pressure: The pressure exerted by the movement of a solvent through a semi-permeable membrane toward equalizing solution concentration on opposite sides of the membrane.

Ossification: The process of bone formation.

Osteitis: Inflammation of a bone.

Osteomalacia: A weakening of the bones due to a calcium, phosphorus, and/or Vitamin D deficiency.

Osteoporosis: An abnormal porousness of bone as the result of a calcium, phosphorus, and/or vitamin D deficiency.

Ovulation: The discharge of the ovum or egg from the graafian follicle of the ovary.

Paba: Para-aminobenzoic acid.

Palmitic acid: A 16-carbon saturated fatty acid.

Palmitin: The fat formed from the reaction of palmitic acid with glycerol.

Pancreas: A large, elongated gland located near the stomach. It produces pancreatic juice which is secreted into the upper small intestine via the pancreatic duct.

Pancreatic Juice: A thick, transparent liquid secreted by the pancreas into the upper small intestine. It contains the enzymes pancreatic amylase, pancreatic lipase, and trypsin; also the hormone insulin.

Pandemic: Widely spread throughout several countries.

Pantothenic acid: One of the B vitamins.

Para-aminobenzoic acid: One of the B vitamins. Often abbreviated PABA.

Parakeratosis: Any abnormality of the outermost or horny layer of the skin.

Paralysis: Loss of power of voluntary motion.

Parathyroid: Any one of four small glands situated beside the thyroid gland, concerned chiefly with calcium and phosphorus metabolism.

Parturition: The act of giving birth to young.

Pasture: Forages which are harvested by grazing animals.

Pathogen: Any disease-producing microorganism or material.

Pathology: The branch of medicine that deals with the special nature of disease.

Pellets: Compacted particles of feed formed by forcing ground material through die openings.

Pentosan: A pentose-based polysaccharide having the general formula (C5H8O4)n. Araban and xylan are examples. Not nearly as abundant as the hexosans.

Pentose: A 5-carbon monosaccharide having the formula C5H10O5. Arabinose, xylose, and ribose are examples. Not abundant in the free form in nature.

Pepsin: The proteolytic enzyme present in the gastric juice. It acts on protein to form proteoses, peptones, and peptides.

Permeable: Capable of being penetrated.

Perspiration: Sweat or the act of sweating.

pH: A measure of hydrogen ion concentration or the degree of acidity.

Phagocyte: Any cell that can ingest particles or cells that are foreign or harmful to the body.

Phenylalanine: One of the essential amino acids.

Phospholipids: Fat-like substances containing phosphorus and nitrogen, along with fatty acids and cholesterol.

Physiological: Pertaining to the science which deals with the functions of living organisms or their parts.

Pituitary: A gland in the lower part of the brain which produces a number of hormones.

Plasma: The colourless fluid portion of the blood in which the corpuscles are suspended.

Polysaccharide: Any one of a group of carbohydrates consisting of a combination of a large but undetermined number of monosaccharide molecules, such as starch, dextrin, glycogen, cellulose, inulin, etc.

Postpartum: Following the birth of young.

Potent: Strong, powerful, concentrated.

Poultry Litter: The fibrous material used on the floor of poultry houses along with the excreta which accumulates therein.

Pre-conceptional: Before pregnancy.

Precursor: A compound that can be used by the body to form another compound.

Pregnant: The state of having a developing embryo in the body. Gravid.

Pre-mix: A uniform mixture of one or more micro-ingredients and a carrier, used in the introduction of micro-ingredients into a larger mixture.

Pressure cooker: An airtight container for the cooking of feed at high temperature under steam pressure.

Progesterone: A sex hormone produced by the corpus lutea of the ovary.

Proline: One of the nonessential amino acids.

Propionic acid: One of the volatile fatty acids with the formula CH3CH2COOH, commonly found in rumen contents but not in silage.

Protein: Any one of many complex organic nitrogenous compounds formed from various combinations of different amino acids.

Protoplasm: The essential protein substance of living cells.

Protozoa: Very small, unicellular animal organisms.

Provitamin: A Carotene.

Puberty: The age at which the reproductive organs become functionally active.

Pulp: The solid residue which remains following the removal of the juices from plant materials.

Putrefaction: The decomposition of proteins by microorganisms under anaerobic conditions.

Pyrexia: A feverish condition.

Pyridoxine: The same as vitamin B6.


Q – S

Radioactive: Giving off atomic energy in the form of alpha, beta, or gamma rays.

Radioisotope: A radioactive form of an element.

Rancid: A term used to describe fats that have undergone partial decomposition.

Range Cubes: Large pellets produced for feeding in the pasture on the ground.

Rennin: The milk-curdling enzyme present in the gastric juice of milk-consuming animals.

Residue: That which remains of any particular substance.

Resorption: A return of the nutritive components of a partially formed fetus and fetal membrane to the system of the mother.

Respiration: The act of breathing.

Reticulum: The second compartment of a ruminant’s stomach. Also called the honeycomb or waterbag.

Riboflavin: Same as vitamin B2. Formerly known as vitamin G.

Rolled: Compressed into flat particles by having been passed between rollers.

Roughage: Any feed high (over about 20%) in crude fibre and low (under about 60%) in TDN, on an air-dry basis. Opposite of concentrate.

Saliva: A clear, somewhat viscid solution secreted by the salivary glands into the mouth. It contains the enzymes salivary amylase and salivary maltase.

Salmonella A pathogenic, diarrhoea-producing organism sometimes present in contaminated feeds.

Saponifiable: Having the capacity to react with alkali to form soap.

Saponification: The formation of soap and glycerol from the reaction of fat with alkali.

Sarcoma: A tumor of fleshy consistency—often highly malignant.

Saturated fat: A fat formed from the reaction of glycerol with any one of several saturated fatty acids. Stearin and palmitin are examples.

Saturated fatty acid: Any one of several fatty acids containing no double bonds. Stearic and palmitic acids are examples.

Sedentary: Sitting most of the time.

Self-fed: Provided with a part, or all, of the ration on a continuous basis, thus permitting the animal to eat at will.

Semi-dispensable amino acid: An amino acid which is essential only under certain circumstances or which may replace in part one of the essential amino acids. Arginine, cystine, and tyrosine fall into this group.

Septicemia: A diseased condition resulting from the presence of pathogenic bacteria and their associated poisons in the blood.

Serine: One of the nonessential amino acids.

Serum: The colourless fluid portion of blood remaining after clotting and removal of corpuscles. It differs from plasma in that the fibrinogen has been removed.

Shorts: A by-product of flour milling consisting of a mixture of small particles of bran and germ, the aleurone layer, and coarse flour.

Silage: The feed resulting from the storage and fermentation of green or wet crops under anaerobic conditions.

Silo: A semi-airtight to airtight structure designed for use in the production and storage of silage.

Soap: A compound formed along with glycerol from the reaction of fat with alkali.

Solid: A substance that does not perceptibly flow.

Solution: A uniform liquid mixture of two or more substances molecularly dispersed within one another.

Solvent process: A process for the extraction of oil from seeds involving the use of an organic solvent.

Specific gravity: The ratio of the weight of a body to the weight of an equal volume of water.

Specific heat: The heat-absorbing capacity of a substance in relation to that of water.

Spore: An inactive reproductive form of certain microorganisms.

Stabilized: Made more resistant to chemical change by the addition of a particular substance.

Starch: A polysaccharide having the formula (C6H10O5)n. An important source of energy for livestock. Yields glucose upon complete hydrolysis.

Stearic acid: An 18-carbon saturated fatty acid which reacts with glycerol to form stearin.

Stearin: The fat formed from the reaction of stearic acid with glycerol.

Sterile: Free from living microorganisms. Also, not capable of producing young.

Sterility: An inability to produce young.

Sterol: One of a class of complex, fat-like substances widely distributed in nature.

Stomach: That part of the digestive tract lying between the oesophagus and the small intestine. A 4-compartment organ in ruminants; a single compartment organ in non-ruminants.

Straw: That part of the mature plant remaining after the removal of the seed by threshing or combining.

Stress: Any circumstance which tends to disrupt the normal, steady functioning of the body and its parts.

Substrate: A substance upon which an enzyme acts. Same as zymolyte.

Sucrase: An enzyme present in intestinal juice which acts on sucrose to produce glucose and fructose.

Sucrose: A disaccharide having the formula C12H22O11. It hydrolyzes to glucose and fructose. Commonly known as cane, beet, or table sugar.

Sun-cured: Dried by exposure to the sun.

Supplement: A semi-concentrated source of one or more nutrients used to enhance the nutritional adequacy of a daily ration or a complete ration mixture.

Syndrome: A medical term meaning a set of symptoms that occur together.

Synthesis: The bringing together of two or more substances to form a new material.


T – V

Tdn: Total digestible nutrients.

Tetany: A syndrome involving sharp flexion of the wrist and ankle joints, muscle twitching, cramps, and convulsions.

Therapeutic: Pertaining to the medical treatment of disease.

Therapy: The medical treatment of disease.

Thermal: Refers to heat.

Thiamine: The same as thiamin, thiamine hydrochloride, or vitamin Bt.

Threonine: One of the essential amino acids.

Thrombosis: The obstruction of a blood vessel by the formation of a blood clot.

Thyroid: The gland in the neck that secretes the hormone thyroxin.

Tocopherol: Any of four different forms of an alcohol which is also known as vitamin E.

Total digestible nutrients: A figure which indicates the relative energy value of a feed to an animal. It is the sum of the digestible protein, digestible nitrogen-free extract, digestible crude fibre, and (2.25 x the digestible fat).

Toxic: Of a poisonous nature.

Trace mineral: Any one of several mineral elements that are required by animals in very minute amounts. Same as micromineral.

Tracer Element: A radioactive element used in biological and other research to trace the fate of a substance.

Trauma: A wound or injury.

True protein: A nitrogenous compound which will hydrolyze completely to amino acids.

Tryptophan: One of the essential amino acids.

Tyrosine: One of the nonessential amino acids.

Unsaturated fat: A fat formed from the reaction of glycerol with any one of several unsaturated fatty acids. Olein and linolein are examples.

Unsaturated fatty acids: Any one of several fatty acids containing one or more double bonds. Oleic, linoleic, linolenic, and arachidonic acids are examples.

Urea: A white, crystalline, water-soluble substance with the formula CO(NH2)2. It is the most extensively used source of non-protein nitrogen for animal feeding.

Urease: An enzyme which acts on urea to produce carbon dioxide and ammonia. It is found in the jackbean and the soybean, and is produced by certain microorganisms in the rumen.

Uremia: A toxic accumulation of urinary constituents in the blood.

Valine: One of the essential amino acids.

Vascular: Pertaining to the blood vessels of the body.

Vfa: Volatile fatty acid(s).

Villi: Small thread-like projections attached to the interior side of the wall of the small intestine.

Viscera: The organs of the great cavities of the body which are normally removed at slaughter.

Viscosity: The freedom of flow of liquids.

Vitamin: One of a group of organic substances which in relatively small amounts are essential for life.

Volatile fatty acid: Any one of several volatile organic acids found especially in rumen contents and/or silage. Acetic, propionic, and butyric acids are ordinarily the most prevalent.


W – Z

Wet-rendered: Cooked with steam under pressure in closed tanks.

Whey: The watery portion of milk remaining after the removal of the fat and curd.

Work: Movement of matter through space.


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